Advances in Immunotherapies for Targeting Cancer Stem Cells in a Tumor Microenvironment: Emerging Strategies and...

Cancer stem cells (CSCs) are a distinct subpopulation within a tumor that play an important role in tumor initiation, metastasis, therapeutic resistance, and cancer relapse. Their persistence is strongly influenced by the tumor microenvironment (TME), which provides a range of biological signals that maintain stemness, promote immune evasion, and resistance to cancer treatment. Therefore, effective targeting of CSCs is essential to improve therapeutic efficacy. In this review, we summarize the key characteristics of CSCs and their niche within the TME, emphasizing their interactions with immune cells, stromal components, and secreted factors. We also discuss the major challenges in targeting CSCs, including immune evasion, metabolic constraints, and intratumoral heterogeneity. We further highlight current and emerging immunotherapeutic strategies targeting CSCs, including immune checkpoint inhibitors, cancer vaccines, monoclonal antibodies, nanobodies, bispecific antibodies, antibody-drug conjugates (ADCs), CAR-T and CAR-NK cell therapies, oncolytic viruses, as well as innovative approaches such as targeted protein degradation. Finally, we emphasize the importance of a combinatorial approach that integrates CSCs targeting with modulation of the TME. Together, these strategies may lead to more durable responses, enhance therapy efficacy and reduce the risk of tumor recurrence.